Covered elastic thread



April 1932- N. A. CRIIMMINS ETAL 1,853,551

NNNNN TORa NEIL A.CRIM INS WILLIAM E' ALDEN ATroRNEY Patented Apr. 12,1932 UNITED STATES PATENT OFFICE NEIL A. CRIMMINS, OF STOUGHTON, ANDWILLIAM. F. ALDEN, OF NEEDHAM, MAS SA- CHUSETTS, ASSIGNORS TO NEIL A.CRIMMINS, INC., OF'STOUGHTON, MASSACHU- SETTS, A. CORPORATION OFMASSACHUSETTS COVERED ELASTIC THREAD Application filed February 5, 1931.

This invention relates to a covered elastic thread adapted to enter theconstruction of knitted, woven and braided fabrics such as are used incorsets, garters, supporters and a variety of other articles.

One object of the invention is to construct a covered elastic threadhaving a corrugated or roughened outer surface which causes it to begripped securely by the sewing machine stitches and held tenaciously inthe knitted, woven or braided fabric, thereby greatly retarding itsslippage through the fabric or the sewing machine stitches.

Another object of the invention is to provide an elastic covered rubberthread having a plurality of covers so constructed and arranged that,when the rubber core is severed by the sewing machine needle, theseveral covers cooperate to form an encasement which decidedly limitsthe separation of the severed ends and encloses them in such a manner asto make the rupture hardly perceptible.

Another object of the invention is to provide an elastic covered rubberthread having a plurality of covers so constructed and 'arranged thatthe breaking points of all the covers are reached at approximately thesame time but well within the elastic limit of the rubber core.

Still another object of the invention is to provide an elastic threadhaving a core composed of one or more rubber strands, and a plurality ofsuperimposed spirally wound textile covers applied in such a mannerthat, while the rubber core may be securely encased and held either at arelatively low tension or extended to its normal stretch, the extensionof the covers may be limited to the desired degree.

In the manufacture of corsets and other garments it is customary to sewsections of elastic fabrics together or to other sections of non-elasticfabrics. When the elastic fabric is made of ordinary covered rubberthread, having the usual smooth outer surface, the sewing machine needleoften enters the spaces between adjacent threads, or sometimes merelypierces the edges of the threads. Consequently, when the elastic fabricis Serial No. 513,492.

stretched, many of the covered rubber threads slip between the sewingmachine stitches, and then through the fabric, causing objectionableimperfections and impairing the utility and value of the garment. Thesewing machine needle may also glance ofl the smooth or hard surface ofthe thread, causing the needle to break with consequent loss inproduction. Sometimes the 'needle severs the rubber core, and when thishappens the edges of the core pull apart in spite of the coveringthreads, leaving an unsightly gap.

Elastic rubber thread is used for the purpose mentioned above because ofits qualities of extension and contraction. It is covered to give addedstrength, prevent deterioration, and to control or regulate the stretchand contraction. The requirements of elastic fabrics are'decidedly infavor of short stretch having a quick contraction to its original lengthafter being stretched, and possession of the greatest strength with aminimum bulk. Some attempts have been made to regulate or limit thestretch of the rubber by laying an inextensible cotton stay threadalongside the rubber, or by twisting threads around the rubber in a longpitched or open spiral. In these instances, however,as the stay threador the long pitched spiral coverings constitute only about 20% of theaggregate tensile strength of the total covering, they are readilybroken and of doubtful further value.

Our improved elastic thread consists of a rubber core composed of one ormore rubber strands having a plurality of cover threads which areWrapped around in superimposedspirals, one entirely outside the other.The innermost cover is preferably wound around the rubber core with ashort pitched spiral. The second cover is wound over the first cover inthe opposite direction, also with a short pitched spiral.' One or moreouter covers are then applied in open or long pitched spirals so as tocompress the first two covers and cause the second cover to bulge outbetween the open outer'spirals, giving the finished thread a very roughor corrugated gripping surface.

The roughened gripping surface of these elastic threads enables thesewing machine 'ELII needle to pierce the body of the threads,preventing the needle from breaking and preventing the threads fromslipping through the fabric. Even if an occasional stitch fails topierce the body of the thread, the rough gripping surface will cling tothe surround ing portions of the fabric and prevent slipping. Theseveral cover threads likewise cooperate to form an encasement whichgrips the rubber core firmly so that, even if the core is ruptured bythe sewing machine needle, the several ends will only separate to alimited extent. In the preferred form of the invention the cover threadsare so arranged and applied that their breaking points are reached atapproximately the same time but well within the elastic limit of therubber core.

Our improved elastic thread renders possible the economical roduction ofthread having the desirable c aracteristics of the more expensivebraided elastic thread, being decidedly more difiicult to unravel thanprevious wrapped threads of this type, and retaining to a far greaterdegree the original encasement formed by the covers to effectuallyconceal and control the rubber core even when it is severed.

The invention will be described in connec- I tion with the accompanyingdrawing which shows one embodiment of our elastic thread ona greatlyenlarged scale, with the covers partly unwrapped.

The elastic thread consists of one or more elastic rubber core threadsor strands 1 on which are wound a plurality of superimposed spi'allywound textile cover threads 2, 3, 4 5.

The innermost cover 2, consisting of one or preferably two ends ofsuitable textlle fibresfis wound upon the rubber core in the usualmanner, preferably with a short pitched close spiral so that itcompletely encloses the rubber core when in the normal contractedcondition shown in the drawing.

The second cover 3 is similar to the first cover, but is preferablycomposed of three ends of textile fibres wound in the opposite directionover the first cover, also in a short pitched close spiral. The covers 2and 3 tother substantially cover and conceal the ruber core even when itisstretched to the limit of its elasticity.

The third cover 4' is preferably composed of one end of hard twistedcotton which is wound tightly over the inner covers in a long pitchedopen spiral running in the opposite direction to the cover 3. The fourthcover 5 is preferably composed of one end of hard twisted yarn which iswound in an opposite direction to the cover 4, also in a long pitchedopen spiral. When a fifth cover is applied the process is similar to thethird and fourth covers.

The covers 2 and 3 serve to protect and breaking point at substantiallythe same time,

well within the elastic limit of the rubber core, limiting the stretchof the rubber, and insuring that the breaking points of the core and allthe covers are reached at approximately the same point.

It will be understood that we do not limit ourselves to any particularnumber of strands in the core or covers, or to the preferred arrangementof spirals which we have shown here for purposes of illustration, as itwill be obvious that various changes may be made without departing fromthe scope and spirit of the invention. as defined in the appendedclaims.

The invention claimed is:

1. A covered elastic thread comprising an elastic rubber core having aplurality of spirally wound superimposed covers applied thereon, oneentirely outside the other, the outermost cover having a greater pitchthan the inner cover and compressing same to form an extensibleencasement gripping the rubber core and limiting the stretch thereof.

2. A covered elastic thread comprising an elastic rubber core having twosuperimposed covers wound thereon'in oppositely directed short pitchedclose spirals, one entirely outside the other, and another cover woundupon the first two covers in a longer pitched open spiral compressingthe first two covers to form an extensibleencasement gripping the rubbercore and limiting the stretch thereof.

3. A covered elastic thread comprising an elastic rubber core, an innercover wound around the core in a short pitched spiral, and an outercover wound around the inner cover in a long pitched spiral compressingthe inner cover and causing it to bulge out between the convolutions ofthe outer cover.

4. A covered elastic thread comprising an elastic rubber core, an innercover wound around the core in a short pitched spiral, and a pair ofouter covers wound around the in ner cover in oppositely directed longpitched spirals compressing the inner cover and causing it to bulge outbetween the convolutions of the outer covers.

5. A covered elastic thread comprising an elastic rubber core having atleast two superimposed inner covers wound-thereon in oppositely directedshort pitched spirals completely covering the core, and at least twoouter covers wound around the inner covers in oppositely directed longpitched open spirals compressing the inner covers and causing them tobulge out between the convolutions of the outer covers to give thethread a rough outer surface.

6. A covered elastic thread comprising an elastic rubber core havin aninner cover wound around it in such a s ort pitched close spiral as tosubstantially cover the core even when stretched, a second cover woundaround the first cover in an oppositely directed short pitched closespiral, and a pair of outer covers wound upon the first two covers inoppositely directed long pitched open spirals compressing the first twocovers and causing the second cover to bulge out between theconvolutions of the outer covers, all of said covers being adapted totighten so as to break at substantially the same point well within theelastic limit of the rubber core.

7. A covered elastic thread comprising an elastic rubber core, an innercover composed of a plurality of ends of fibrous material wound aroundthe core in a short pitched close spiral completely enclosing the corewhen in normal contracted condition, a second cover composed of aplurality of ends of fibrous material wound around the first cover inan. oppositely directed short pitched close spiral cooperating with thefirst cover to substantially conceal the core even when stretched to thelimit of its elasticity, and a pair of outer covers composed of hardtwisted fibrous material wound upon the first two covers in oppositelydirected long pitched open spirals compressing the first two covers'andcausing the second cover to bulge out between the convolutions of theouter covers, all of said covers being adapted to tighten and reach thebreaking point at substantially the same time well within the elasticlimit of the rubber core.

Signed at Stoughton, in the county of Norfolk and State of Massachusettsthis 30 day of January A. D. 1931.

NEIL A. CRIMMINS'. WILLIAM F. ALDEN.

